Synthetic aperture imaging with intensity-only data

We consider imaging the reflectivity of scatterers from intensity-only data recorded by a single moving transducer that both emits and receives signals, forming a synthetic aperture. By exploiting frequency illumination diversity, we obtain multiple intensity measurements at each location, from which we determine field cross-correlations using an appropriate phase controlled illumination strategy and the inner product polarization identity. The field cross-correlations obtained this way do not, however, provide all the missing phase information because they are determined up to a phase that depends on the receiver's location. The main result of this paper is an algorithm with which we recover the field cross-correlations up to a single phase that is common to all the data measured over the synthetic aperture, so all the data are synchronized. Thus, we can image coherently with data over all frequencies and measurement locations as if full phase information was recorded

Synthetic Aperture Imaging With Intensity-Only Data.

We consider imaging the reflectivity of scatterers from intensity-only data recorded by a single moving transducer that both emits and receives signals, forming a synthetic aperture. By exploiting frequency illumination diversity, we obtain multiple intensity measurements at each location, from which we determine field cross-correlations using an appropriate phase controlled illumination strategy and the inner product polarization identity. The field cross-correlations obtained this way do not, however, provide all the missing phase information because they are determined up to a phase that depends on the receiver's location. The main result of this paper is an algorithm with which we recover the field cross-correlations up to a single phase that is common to all the data measured over the synthetic aperture, so all the data are synchronized. Thus, we can image coherently with data over all frequencies and measurement locations as if full phase information was recorded

Investigation of microwave antennas in lossy media for medical applications

For several years, microwave engineers have dreamed of using non-ionising electromagnetic waves in medical imaging applications. The rate of evolution of microwave techniques for medical application has been immense and shows no signs of relenting. Since the limitations of X-ray mammography are well reported, alternative techniques using microwaves for breast cancer detection are developed. Some of these techniques have progressed to the point where positive clinical experience has emerged

THREE-DIMENSIONAL HOLOGRAPHIC MICROWAVE IMAGING ARRAY: EXPERIMENTAL INVESTIGATION OF TUMOUR DETECTION IN BREAST PHANTOM

ABSTRACT This paper extends our previously presented twodimensional (2-D) Holographic Microwave Imaging Array (HMIA) system for early breast tumour detection to threedimensional (3-D) imaging, and demonstrates its efficacy using experimental data obtained with a breast phantom. This work describes an experimental setup to collect data to form a 3-D breast image. The obtained experimental result proves that the 3-D HMIA system has potential to become a screening and diagnostic tool that could supplement clinical breast examination through its sensitivity, quantitative record storage, ease-of-use, and inherent low cost

Experimental Synthetic Aperture Radar with Dynamic Metasurfaces

We investigate the use of a dynamic metasurface as the transmitting antenna for a synthetic aperture radar (SAR) imaging system. The dynamic metasurface consists of a one-dimensional microstrip waveguide with complementary electric resonator (cELC) elements patterned into the upper conductor. Integrated into each of the cELCs are two diodes that can be used to shift each cELC resonance out of band with an applied voltage. The aperture is designed to operate at K band frequencies (17.5 to 20.3 GHz), with a bandwidth of 2.8 GHz. We experimentally demonstrate imaging with a fabricated metasurface aperture using existing SAR modalities, showing image quality comparable to traditional antennas. The agility of this aperture allows it to operate in spotlight and stripmap SAR modes, as well as in a third modality inspired by computational imaging strategies. We describe its operation in detail, demonstrate high-quality imaging in both 2D and 3D, and examine various trade-offs governing the integration of dynamic metasurfaces in future SAR imaging platforms

Investigation of microwave antennas in lossy media for medical applications

For several years, microwave engineers have dreamed of using non-ionising electromagnetic waves in medical imaging applications. The rate of evolution of microwave techniques for medical application has been immense and shows no signs of relenting. Since the limitations of X-ray mammography are well reported, alternative techniques using microwaves for breast cancer detection are developed. Some of these techniques have progressed to the point where positive clinical experience has emerged.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

Design of a Pseudo-Holographic Distributed Time-of-Flight Sonar Range-Imaging System

The design of an audible sonar distributed sensor time-of-flight range imaging system is investigated, sonar being chosen as a substitute for optical range imaging due to cost and simplicity of implementation. The distributed range imaging system proposed is based on the holographic principle where the sensors detect the self interference of the reflected sound from the scene, and the Fourier analysis computes the reflected object profile. An approximate linearised model used in related holographic imaging techniques is found to be inappropriate for the design, and qualitative assessment of simulations show that removing the linearisation dramatically improves image reconstruction. Quantitatively the nonlinear reconstruction improves the RMSE by a factor of 1.3-2.1 times. The full nonlinear reconstruction is slow, and mathematical development lead to 15 fold reduction in computation time

Holography: A survey

The development of holography and the state of the art in recording and displaying information, microscopy, motion, pictures, and television applications are discussed. In addition to optical holography, information is presented on microwave, acoustic, ultrasonic, and seismic holography. Other subjects include data processing, data storage, pattern recognition, and computer-generated holography. Diagrams of holographic installations are provided. Photographs of typical holographic applications are used to support the theoretical aspects